Structural Analysis by X-Ray Diffraction of a Polar Mesogen 4-Cyanobiphenyl-4'-heptylbiphenyl Carboxylate

Haldar, S and Mandal, PK and Prathap, SJ and Row, TN Guru and Dabrowski, R (2009) Structural Analysis by X-Ray Diffraction of a Polar Mesogen 4-Cyanobiphenyl-4'-heptylbiphenyl Carboxylate. In: Molecular Crystals and Liquid Crystals, 503 . pp. 99-111.

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Abstract

Crystal and molecular structure of a compound 4-cyanobiphenyl-4'-heptylbiphenyl carboxylate (7CBB), which exhibit both monolayer smectic A and nematic phases, have been determined by direct methods using single crystal X-ray diffraction data. The structure is monoclinic with the space group P21/c and Z = 4. The unit cell parameters are a = 16.9550(5) Aring, b = 5.5912(18) Aring, c = 27.5390(9) Aring, agr = 90.000°, β = 93.986(6)°, and γ = 90.000°. Packing of the molecules is found to be precursor to SmC phase, although SmA1 phase is observed on melting. Several strong van der Waals interactions are observed in the core part of the neighboring molecular pairs. Crystal to mesophase transition is probably of reconstitutive nature. Geometry, packing, and nature of crystal-mesophase transition are compared to those in 6CBB.

Item Type:	Journal Article
Publication:	Molecular Crystals and Liquid Crystals
Publisher:	Taylor and Francis
Additional Information:	Copyright of this article belongs to Taylor and Francis Group.
Keywords:	crystal and molecular structure;crystal-mesogen transition; molecular packing;reconstitutive transition;smectogen;van der Waals interaction
Department/Centre:	Division of Chemical Sciences > Solid State & Structural Chemistry Unit
Date Deposited:	04 Jan 2010 05:27
Last Modified:	19 Sep 2010 05:35
URI:	http://eprints.iisc.ac.in/id/eprint/20987

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